1. Field of the Invention
The invention relates to three-dimensional microelectrode arrangements and processes for shaping suspended particles (particles, phases) or droplets of a liquid in electric fields, preferably high frequency fields, and to solidify or consolidate them under field influence. The invention also relates to certain uses of the shaped particles.
2. Prior Art
Numerous separation techniques in chemistry, medicine or biotechnology are based on the streaming through packed volumes of small particles serving as filters or carriers with extended function. In chromatography for example, there is frequent use of spherical gel particles (e. g. Sephadex), irregular granulates (activated coals, resins, mixed oxides), extruded and compressed substances.sup.1 (molecular sieves, catalysts) or fibers and hollow fibers (Ullmanns Encyclopedia of Industrial Chemistry, Vol. A21, 305-428 (1992) VCH-Publishers Cooperation, as well as in the place cited Vol. B3, 10-1 to 10-44 (1992)). Spherical microparticles are also frequently used in dyestuff production because of their characteristic optical refraction features as a function of their size (e. g. latex or microspherical glasses in or with light reflecting paintings). On the one hand, smaller and smaller particle dimensions (micrometer range, submicrometer range) are sought to be obtained (Kirk-Othmer, Encyclopedia of Chemical Technology, Vol. 15, 470-493 (1981), J. Wiley & Sons, New York), or, on the other hand, importance is attributed to a defined size spectrum--up to monodisperse homogeneous mixtures--, in order to obtain, with a given packed volume, larger and larger surfaces for reciprocal effect with the liquid, gas or suspension streaming through. FNT .sup.1 in German "Extruder-Komprimate"
The size of the exclusively spherical end products in the micrometer or submicrometer range may be strictly determined only by the processing conditions of production or adjusted by subsequent classification. The latter is valid for all irregular particles proceeding from size reduction technologies, but not for their shape. The shape of the microparticles results exclusively from their production technology and is limited to microspheres (balls) by melting technologies for all polymer materials and the aforementioned glasses produced in stirred tank reactors. Only microcrystalline materials are subject to a certain regulation or control, the shapes to be obtained resulting from the projection of the material specific crystal levels and for this reason again being limited.